Sure, though the equity refreshes done at Google are done yearly targeting a $$ range at the current share price, and then vesting over multiple years. So even if the stock goes down it will tend to amortize out to about the same over a number of years, and if the stock goes up a bunch again older grants made "at the bottom" could even net you big results.

But of course there's also the chance that not only will Google's stock go down, but their revenues... and generosity... will to.

Me, I "lucked out" and sold my RSU at the peak. Though I've been living off the cash proceeds since, so.